National Repository of Grey Literature 33 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The effect of Bisphenol S on porcine oocyte meiotic maturation
Kosařová, Zuzana ; Petr, Jaroslav (advisor) ; Kaňka, Jiří (referee)
Meiotické zrání je klíčovou fází vývoje samičích gamet. Do regulace procesu zrání mohou negativně zasahovat látky, které vstupují do organismu z vnějšího prostředí a následně narušují homeostázu na úrovni hormonálního řízení. Tyto látky se označují jako endokrinní disruptory (ED). Mezi nejrozšířenější ED patří bisfenoly. Po prokázání ED aktivity a právních regulacích využití bisfenolu A značně stoupla světová produkce bisfenolu S (BPS). Recentní studie potvrzují negativní vliv BPS přítomného v organismu na reprodukci lidí a zvířat. Přesto zůstává řada dopadů BPS na oogenezi stále nejasná. Tato práce je zaměřena na hodnocení vlivu BPS na vybrané markery rozpadu jaderné membrány v průběhu rozpadu zárodečného váčku (lamin A/C, lamin B1 a LEMD3) a na přeskupování chromatinu po výstupu prasečích oocytů z I. meiotického bloku. Výsledky prokazují negativní vliv BPS na průběh meiotického zrání zrychlením či zpomalením dějů, které souvisejí s rozpadem jaderné membrány a na nutnost se tímto tématem dále zabývat. Klíčová slova endokrinní disruptor, bisfenol S, meiotické zrání, rozpad jaderné membrány, oocyt
Regulation of development of mouse parthenogenetic embryos
Jettmarová, Dominika ; Fulka, Josef (advisor) ; Kaňka, Jiří (referee)
The development of mouse (Mus musculus) haploid parthenogenetic embryos does not reach the same level as normal embryos. The aim of this diploma thesis was to find out whether haploid parthenogenetic embryos of mice differ in the nucleocytoplasmic ratio. The volume of the nucleus increases with ploidity. The nucleocytoplasmic ratios of haploid embryos do not significantly change between the two-cell and four-cell stage (p = 0.052), there is a significant difference (p < 0.001) for diploid and tetraploid embryos. Non-standard nucleocytoplasmic ratio could be related to the problematic development. Understanding the regulation of preimplantational development of parthenogenetic embryos will increase the efficiency of haploid embryonic stem cell derivation.
The expression and function of nucleophosmin (B23) during bovine preimplantation development
Benešová, Veronika ; Kaňka, Jiří (advisor) ; Krylov, Vladimír (referee)
Identification of genes that start their expression in different time of embryonal development is crucial for proper understanding of early mammalian embryogenesis. Genes that are differently expressed during this period are supposed to be important for normal preimplantation development. One of these genes is nucleophosmin, the multifunctional protein, which functions among others as a transporting protein between cytoplasm and nucleoli. It is involved in duplication of centrosomes, formation of ribosomes and functions as a chaperoning protein. Nucleophosmin shuttles rapidly between the nucleolus and cytoplasm. Its localization is cell cycle dependent and reflects the development of the nucleoli. For studying the effect of nucleophosmin on the bovine preimplantation development we used RNA interference that causes degradation of the target mRNA after injection of nucleophosmin double-stranded RNA. The average decrease of nucleophosmin mRNA abundance is 86.3 % between nucleophosmin dsRNA injected embryos and control group. We detected no differences in protein expression and localization of nucleophosmin between the groups by immunofluorescence method. Embryos in all groups were able to develop until the blastocyst stage, although there were significant difference between uninjected control group and...
The effect of diabetes mellitus on reproductive parameters and expression of selected testicular genes in diabetic mice
Valášková, Eliška ; Pěknicová, Jana (advisor) ; Kaňka, Jiří (referee)
According to the World Health Organization (WHO), 15% of couples in reproductive age suffer from infertility problems, and up to 60% of cases are caused by male factor. Causes of this condition could be genetic background, environmental factors and various diseases, including diabetes mellitus (DM). The aim of this study was to investigate the effects of DM on reproductive parameters and expression of selected testicular genes using mouse model (FVB inbred mouse strain). DM (type 1) was artificially induced by chemical substance streptozotocin, which causes destruction of pancreatic β cells. These mice were exposed to diabetic condition for 6 weeks and then subjected to analysis. Our results have shown that diabetic condition had an impact on body weight, weight of reproductive organs as well as kidneys and livers. We also observed decreased concentration and viability of diabetic sperm compared to control. Moreover, we noticed increased staining with apoptotic marker annexin V. Further, we evaluated changes of sperm nuclear proteins - protamines. In diabetic animals, we observed higher number of sperm with insufficient protamination. Nevertheless, protamine 1 to protamine 2 ratio (P1/P2), a marker of male fertility, was not altered in sperm of diabetic animals compared to control. Regarding the...
Analysis of functional interactions of phospholipids in the cell nucleus.
Biddle, Veronika ; Hozák, Pavel (advisor) ; Kaňka, Jiří (referee) ; Malínský, Jan (referee)
(English) Phosphoinositides (PIs) are glycerophospholipids with a negative charge. As components of cell membranes, PIs are involved in membrane and cytoskeletal dynamics, cell movement and signalling, and the modulation of ion channels and transporters. Apart from the cytoplasm, phosphoinositides also localise to the cell nucleus. PIs play a role in crucial nuclear processes, such as DNA transcription, pre-rRNA and pre-mRNA processing, cell differentiation, DNA damage response, or apoptosis. Phosphatidylinositol 4-phosphate (PI(4)P) and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) are the most abundant phosphoinositides in the cell. However, their exact localisation and function in the nucleus are largely unknown. Here, we describe their localisation at super-resolution level and their involvement in some nuclear processes. PI(4)P is present in nuclear lamina, nuclear speckles and nucleoli, and it forms small foci in nucleoplasm. The majority of nuclear PI(4)P localises to the nucleoplasm, whereas almost 16 % is present in nuclear speckles. On the other hand, the majority of nuclear PI(4,5)P2 localises to nuclear speckles, almost 30 % localises to nucleoplasm and the lesser portion to nucleoli. In the nucleoplasm, PI(4,5)P2 forms small foci called nuclear lipid islets (NLIs). Their core is...
Involvement of protein vinculin in mammalian gametogenesis
Darášová, Alžběta ; Hozák, Pavel (advisor) ; Kaňka, Jiří (referee)
One of the basic characteristics of living systems is a sexual reproduction, when the germ cells, sperm and egg, fuse. The key process in the germ cells development is meiosis. During meiotic division, several dramatic changes happen in the nucleus and different errors might appear, which may then result in various chromosomal aberrations and nondisjunctions leading to genetic diseases and infertility. The causes of infertility are very diverse, but many of them obviously come from the meiotic errors. One of the most critical parts for the successful meiotic progress is a prophase I, where the homologous chromosomes are paired by the protein structure of the synaptonemal complex (SC) and subsequent genetic recombinations by crossing- over accurate. Vinculin (VCL) is a cytoplasmic actin binding protein in the focal adhesions and adherent junctions and VCL acts as their essential regulator. Recently, this protein was also found in the nucleus of germ cells of certain organisms. However, the nuclear functions of vinculin have not been described yet. This diploma thesis focuses on the study of chromosomal dynamics in the gametogenesis of our mouse model, regarding the involvement of the nuclear vinculin in these processes. Our aim was to localize VCL in the nucleus of embryonic prophase oocytes using...
Regulation of development of mouse parthenogenetic embryos
Jettmarová, Dominika ; Fulka, Josef (advisor) ; Kaňka, Jiří (referee)
The development of mouse (Mus musculus) haploid parthenogenetic embryos does not reach the same level as normal embryos. The aim of this diploma thesis was to find out whether haploid parthenogenetic embryos of mice differ in the nucleocytoplasmic ratio. The volume of the nucleus increases with ploidity. The nucleocytoplasmic ratios of haploid embryos do not significantly change between the two-cell and four-cell stage (p = 0.052), there is a significant difference (p < 0.001) for diploid and tetraploid embryos. Non-standard nucleocytoplasmic ratio could be related to the problematic development. Understanding the regulation of preimplantational development of parthenogenetic embryos will increase the efficiency of haploid embryonic stem cell derivation.
Effect of selected endocrine disruptors on the male mouse reproductive system in vivo
Žatecká, Eva ; Pěknicová, Jana (advisor) ; Kubelka, Michal (referee) ; Kaňka, Jiří (referee)
In our environment there are many compounds which can negatively influence humans and wildlife. Every day, a vast number of environmental pollutants are released into our environment and there is no way to avoid their exposure. Some of these compounds can even mimic endogenous hormones and interfere with our endocrine system (so called endocrine disruptors), which is the key regulatory system controlling almost all physiological processes in human and animal bodies. Also the reproductive system is largely regulated by various hormones, and their proper function is crucial for gamete formation, fertilization and embryo development. Environmental pollutants are therefore considered as one of the possible causes of increased infertility in human population. This prompted us to study the effect of two endocrine disruptors (tetrabromobisphenol A - TBBPA, and zearalenone - ZEA) on the male mouse reproductive system in vivo. According to our results, TBBPA is able to induce apoptosis as well as changes in the expression of selected testicular genes and sperm protamination. Our results also suggest that permanent exposure to TBBPA slightly enhances its effect in the next generation, depending on whether the parents have been affected or not. We hypothesized that differential protamination of the sperm DNA...
The effect of diabetes mellitus on reproductive parameters and expression of selected testicular genes in diabetic mice
Valášková, Eliška ; Pěknicová, Jana (advisor) ; Kaňka, Jiří (referee)
According to the World Health Organization (WHO), 15% of couples in reproductive age suffer from infertility problems, and up to 60% of cases are caused by male factor. Causes of this condition could be genetic background, environmental factors and various diseases, including diabetes mellitus (DM). The aim of this study was to investigate the effects of DM on reproductive parameters and expression of selected testicular genes using mouse model (FVB inbred mouse strain). DM (type 1) was artificially induced by chemical substance streptozotocin, which causes destruction of pancreatic β cells. These mice were exposed to diabetic condition for 6 weeks and then subjected to analysis. Our results have shown that diabetic condition had an impact on body weight, weight of reproductive organs as well as kidneys and livers. We also observed decreased concentration and viability of diabetic sperm compared to control. Moreover, we noticed increased staining with apoptotic marker annexin V. Further, we evaluated changes of sperm nuclear proteins - protamines. In diabetic animals, we observed higher number of sperm with insufficient protamination. Nevertheless, protamine 1 to protamine 2 ratio (P1/P2), a marker of male fertility, was not altered in sperm of diabetic animals compared to control. Regarding the...

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